The blue wall refers to the collection of states whose electoral votes often went to the Democratic presidential candidate. In 2016, Trump lost three states: Pennsylvania, Michigan and Wisconsin. And in 2020, the trio turned blue again, going to President Joe Biden.

The three key states, which together account for 44 electoral votes, have yet to be nominated for Harris or Trump in the 2024 race. A win in the three states would likely result in either candidate reaching the 270 electoral vote threshold needed to win the White House.

With Trump's victory in the battleground state of North Carolina, the Republican candidate becomes the first candidate to win a swing state on Tuesday evening. He also won victories in Republican strongholds like Florida and Ohio, while Harris won in several East Coast states, including Maryland and New York.